ONS refines method to estimate excess deaths

As the UK emerges from the ravages of the pandemic, the Office for National Statistics (ONS) has announced a new method for estimating excess deaths in the UK.1 Measurement of excess deaths became widely used in 2020when timely data on the effect of covid-19 on mortality was vital for monitoring the spread of the virus and developing strategies for controlling it. ONS calculated excess deaths simply as the number of extra deaths occurring in the current period relative to an expected number, which was generally taken as the average number of deaths in the preceding five years.

However, this measure had several limitations.2 It didn’t take account of underlying demographic changes that influence the number of deaths, such as the UK’s increasing and ageing population—both of which would increase expected deaths even in the absence of a pandemic.3 For example, ONS data showed that numbers of deaths in England and …